The present invention relates to calculators which are mainly used as desk calculators performing functional calculations and financial calculations.
Conventionally, there is a calculator which is adapted to display on a common display portion input digits and symbols used for performing arithmetic operations and functional operations. FIG. 8 shows key operations and corresponding displays caused by the respective key operations in such a conventional calculator. In FIG. 8, "A" shows that the calculator is cleared, and "B" shows that an expression "5.times.12" is inputted from the keys. When a digit "1" of the number "12" is required to be deleted, a cursor-shift key is operated twice to move a cursor back to the position of the digit "1", as shown in "C". Thereafter, depression of a "DEL" key causes the digit "1" to be deleted, and then causes the cursor to move to the position of the digit "2", as shown in "D". Another depression of the "DEL" key deletes the digit "2".
In operation of the aforementioned calculator, symbols representing operational orders and numerical digits are inputted and displayed at the cursor position. Deletion of input digits therefore requires that the cursor be moved to each position of the digits to be deleted using the cursor-shift key and that each time the cursor is shifted, the "DEL" key be operated for deleting the digits sequentially one by one. Therefore, when the digits are required to be cleared immediately after they are inputted, the operation of the cursor-shift key and the "DEL" key must inconveniently be carried out repeatedly in accordance with the number of the digits to be deleted.